Revealing mistake: When the shark first attacks and bites off Jim's arm, you can briefly see his real arm under his shirt as he's screaming in pain. (00:34:10)
Revealing mistake: As soon as the three survivors are coming out of the lab through the hatch underwater, they all signal each other to rise to the top. Look at Saffron Burrows, her cheeks are full of air and you can almost see the surface above her head. You can also see the exact same shot when she is about to be eaten by the last shark. And what's with that hand gesture - to cut or for the shark to stop? (01:26:30 - 01:33:10)
Suggested correction: Her cheeks are like that because when we all take in a big breath of air and hold it so not to breathe, that's what happens. The hand gestures when she goes in the water is so the blood can mix with the water so the shark can smell it.
The hand gesture the entry is referring to is just before she is eaten by the shark, the actress waves her hand across her neck area, allegedly to indicate to the director that she was running out of air.
I think she is giving the shark a sign... like stop or don't attack or something like that. So I think she is giving the shark a sign because right after she does that the shark stops swimming towards her.
Maybe in the context of the film you could argue that, but for scenes in which actors are performing underwater, they use that gesture to let the director know they are running out of air.
If you look EXTREMELY closely in one shot with the girl at a close distance and the shark far away you can tell the girl is actually computer animated. So I think she is giving the shark a sign cuz right after she does that the shark stops swimming towards her. But I could be wrong... that's just what I think.
Revealing mistake: At the end of the film, when Preacher is fighting the shark, we can see that it is a white stuntman doing the scene for LL Cool J. (01:28:00)
Revealing mistake: In the scene where L.L. Cool J. is in the flooded kitchen and the shark comes in through the door, he climbs up a shelf, then falls in the water, then climbs out again. Before he makes his way to the oven you can clearly see that under his pants he is wearing knee pads. (00:53:35)
Revealing mistake: In the shot when the helicopter is about to crash into the building, take a look at the blade. There is a wire holding the helicopter.
Revealing mistake: When Samuel L. Jackson is attacked and killed by the shark, you can clearly tell that he is CGI. His arms and legs are segments and it looks really corny. (01:00:05)
Revealing mistake: When Blake and Dr Susan McAlester (Saffron Burrows) emerge to survey the damaged research facility, you can clearly see coastline in the background, although earlier in the movie we see a weather map showing the facility clearly way out in the the ocean. (00:23:25 - 01:29:20)
Revealing mistake: In the wet lab, just after the helicopter explodes into the tower, pieces of concrete are falling all around Thomas Jane, as he reaches to pull the blonde out of the water. The pieces of 'concrete' bounce all around like the foam pieces they are, not actual concrete.
Revealing mistake: Towards the end of the film after Carter is being dragged along by the shark, and shot by the priest, his wound does not bleed at all.
Revealing mistake: As one of the lab crew is showing Tomas Jane the suspended tiger shark you can see a horizontal line in the water in the background. this is the edge of the water tank used to film the exterior scenes (mentioned in DVD extras).